Wireless communication device, electronic timepiece, wireless communication method, and recording medium

ABSTRACT

Peripherals and send timing information presenting a timing of acquiring time information to a central. The central changes the timing in the received timing information so that the timing presented by the timing information received from the peripheral does not overlap with the timing presented by the already received timing information of the other peripheral. The central makes the peripheral change a setting of the timing information based on the changed timing information.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Japanese Patent Application No.2015-123482, filed on Jun. 19, 2015, the entire disclosure of which isincorporated by reference herein.

FIELD

This application relates generally to a wireless communication device,electronic timepiece, wireless communication method, and non-transitoryrecording medium.

BACKGROUND

In recent years, wireless communication devices conducting wirelesscommunication based on Bluetooth (registered trademark), which is ashort distance wireless communication standard, have increasingly beenin use.

For example, Unexamined Japanese Patent Application Kokai PublicationNo. 2009-118403 discloses a time correction system comprising acell-phone device and wrist watch type terminal device conducting shortdistance wireless communication. In this time correction system, thecell-phone device sends time information to the wrist watch typeterminal device and the wrist watch type terminal device corrects themeasured time based on the time information.

Triggered by a user operation or an internal event within the cell-phonedevice that occurs periodically, the time information is sent andreceived. Moreover, the time information is sent and received again ifthe response time of the wrist watch type terminal device to respondwith notice of completion of time adjustment since the time informationis sent by the cell-phone device exceeds a given time period.

When a cell-phone device and a wrist watch type terminal device conductshort distance wireless communication as in the Unexamined JapanesePatent Application Kokai Publication No. 2009-118403, the wrist watchtype terminal device sends advertisement to the cell-phone device andthe cell-phone device responds with a connection request, whereby theconnection is established. Here, the advertisement is notificationinformation for giving notice of presence of the self.

A prerequisite for realizing the transmission/reception of timeinformation in the Unexamined Japanese Patent Application KokaiPublication No. 2009-118403 is that the connection is established asdescribed above. Therefore, the wrist watch type terminal device has tobe so programmed as to send advertisement at a timing corresponding to auser operation or an internal event that occurs periodically in thecell-phone device.

The Unexamined Japanese Patent Application Kokai Publication No.2009-118403 describes embodiments in all of which the cell-phone deviceand wrist watch type terminal device deal with each other on aone-to-one basis. In other words, no embodiment is described in whichthe cell-phone device time-synchronizes multiple wrist watch typeterminal devices.

Generally, specification for simultaneously connecting multiple wristwatch type terminals to the same cell-phone device is complex and thenecessity of such a configuration is rare. Therefore, presumably, thecell-phone device in the Unexamined Japanese Patent Application KokaiPublication No. 2009-118403 is specified to establish connection to onewrist watch type terminal device at a time where there are multiplewrist watch type terminal devices to connect.

Moreover, normally, the initial value for timing transmission ofadvertisement for automatic time correction (the automatic timecorrection time) is set to the same time for all wrist watch typeterminal devices. This is because even if the initial values for thetiming are randomly set, the timings may overlap and some difficulty inmass production may arise.

Therefore, when the cell-phone device time-synchronizes multiple wristwatch type terminal devices in the time correction system of theUnexamined Japanese Patent Application Kokai Publication No.2009-118403, the timings of connection for automatic time correction ofmultiple wrist watch type terminal devices are set to the same time (forexample, 5:00 AM) in some cases. In such cases, the multiple wrist watchtype terminal devices send advertisement to the cell-phone device all atonce at the timing of connection. However, the cell-phone device cannotestablish connection to multiple wrist watch type terminal devices atthe same time; therefore, unsuccessful connection occurs. Asunsuccessful connection occurs, the wrist watch type terminal device isnot time-synchronized.

SUMMARY

Thus, the present disclosure is made with the view of the abovecircumstances and an objective of the disclosure is to provide awireless communication device and the like realizing timesynchronization even where there are multiple wireless communicationdevices to time-synchronize.

In order to achieve the above objective, the wireless communicationdevice according to a first exemplary aspect of the present disclosureis

a wireless communication device comprising a processor, wherein

the processor

measures time;

acquires time information from another wireless communication device andcorrects the measured time;

sends timing information presenting a timing of acquiring the timeinformation to the other wireless communication device; and

receives notice of change of the timing information from the otherwireless communication device and changes a setting of the timinginformation based on the notice of change.

Moreover, in order to achieve the above objective, the wirelesscommunication method according to a second exemplary aspect of thepresent disclosure comprises:

a timing information reception step of receiving from a wirelesscommunication device timing information presenting a timing of thewireless communication device acquiring time information;

a determination step of determining whether the timing presented by thetiming information received in the timing information reception stepoverlaps with a timing presented by timing information of anotherwireless communication device other than the wireless communicationdevice;

a timing information change step of changing the timing presented by thetiming information when the overlapping is determined in thedetermination step; and

a change notification step of sending to the wireless communicationdevice notice of change to change a setting of the timing information ofthe wireless communication device based on the changed timinginformation.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of this application can be obtained whenthe following detailed description is considered in conjunction with thefollowing drawings, in which:

FIG. 1 is an illustration showing an exemplary configuration of thewireless communication system according to an embodiment;

FIG. 2 is a block diagram showing an exemplary configuration of thecentral according to the embodiment;

FIG. 3 is a block diagram showing an exemplary configuration of aperipheral according to the embodiment;

FIG. 4 is a flowchart showing examples of the control procedures tocorrect the time and change the timing information;

FIG. 5 is a block diagram showing an exemplary configuration of thecentral according to a modified embodiment; and

FIG. 6 is a block diagram showing an exemplary configuration of aperipheral according to the modified embodiment.

DETAILED DESCRIPTION Embodiment

An embodiment of the present disclosure will be described hereafter withreference to the drawings. As shown in FIG. 1, a wireless communicationsystem 1 according to an embodiment of the present disclosure comprisesa central 100 that is a wireless communication device, and multipleperipherals 201 and 202 that are other wireless communication devicesdifferent from the central 100.

The central 100 and peripherals 201 and 202 wirelessly communicate witheach other based on the Bluetooth (registered trademark) low energy (theBLE, hereafter). The BLE is a standard (mode) designed for the purposeof low power consumption among the short distance wireless communicationstandards called Bluetooth (registered trademark).

Here, the central 100 provides service to the peripherals 201 and 202.The peripherals 201 and 202 use the service provided by the central 100.

The central 100 and peripherals 201 and 202 are each, for example, aportable terminal capable of wireless communication based on the BLEsuch as a cell-phone, smart-phone, tablet type personal computer, notetype personal computer, and timepiece.

In this embodiment, by way of example, the central 100 is a smart-phoneand the peripherals 201 and 202 are each an electronic timepiecereceiving from the central 100 and displaying on a display 250 variousdata.

The configuration of the central 100 according to this embodiment willbe described hereafter. As shown in FIG. 2, the central 100 comprises awireless communicator 110, a read only memory (ROM) 120, a random accessmemory (RAM) 130, an operator 140, a display 150, and a controller 160.

The wireless communicator 110 comprises, for example, a radio frequency(RF) circuit, base band (BB) circuit, large scale integration (LSI)circuit, or the like. The wireless communicator 110 sends/receivessignals via an antenna 111 and conducts BLE-based wireless communicationwith the peripherals 201 and 202 that are other wireless communicationdevices.

The ROM 120 comprises a nonvolatile memory such as a flash memory andstores programs and various data (for example, timing information and/orclock rate information received from the peripherals 201 and 202) forthe controller 160 to control various functions.

The RAM 130 comprises a volatile memory and is used as the work area inwhich the controller 160 temporarily stores data for conducting variousoperations.

The operator 140 comprises a touch panel and the like, and serves as aninterface used by the user for entering orders.

The display 150 comprises, for example, a liquid crystal display (LCD),electroluminescence (EL) display, or the like, and displays imagesaccording to image data entered from the controller 160.

The controller 160 comprises, for example, a central processing unit(CPU). The controller 160 executes various programs stored in the ROM120 (for example, the program for realizing the control proceduredescribed later) to control the entire operation of the central 100.

The functional configuration of the controller 160 of the central 100 isdescribed next. The controller 160 functions as an advertisementreceiver 161, a connection request transmitter 162, a timing informationreceiver 163, a determiner 164, a timing information changer 165, achange notifier 166, a timekeeper 167, a clock signals generator 168,and a disconnection request transmitter 169.

The advertisement receiver 161 receives advertisement sent from theperipherals 201 and 202 via the antenna 111 and wireless communicator110 based on a scan order. Here, the advertisement is notificationinformation for the peripherals 201 and 202 to give notice of presenceof themselves. A user operation for the scan order may possibly be, forexample, activating an application for using service of the central 100.Moreover, the scan order is not limited to a user operation and may bemade periodically after the application is activated. Here, theadvertisement receiver 161 corresponds to notification informationreception means.

The connection request transmitter 162 sends a connection request forrequesting connection of the peripherals 201 and 202 via the wirelesscommunicator 110 and antenna 111. The connection request is sent whenthe connection is necessary after the advertisement sent from theperipherals 201 and 202 is received. However, the central 100 cannotestablish connection to multiple peripherals 201 and 202 at the sametime. Therefore, the connection request is sent to either one of themultiple peripherals 201 and 202. Here, the connection requesttransmitter 162 corresponds to connection request means.

The timing information receiver 163 receives timing information sentfrom the peripherals 201 and 202 via the antenna 111 and wirelesscommunicator 110. Here, the timing information is information presentinga timing of the peripheral 201 or 202 connecting to the central 100 andacquiring the time information from the central 100. The received timinginformation is stored in the ROM 120 in association with identificationinformation of the transmission source peripheral.

The determiner 164 determines whether the timing presented by the timinginformation received by the timing information receiver 163 from aperipheral (for example, the peripheral 201) overlaps with the timingpresented by the timing information already received from anotherperipheral (for example, the peripheral 202).

When there is no timing information already received from anotherperipheral, the determiner 164 determines that there is no overlappedtiming without the necessity of comparing the timing presented by thereceived timing information with the timing presented by other timinginformation. The determiner 164 determines that there is no overlappedtiming when null data are received from a peripheral instead of timinginformation as well.

Here, the null data means empty data and are sent from a peripheral whenno timing information is sent because it falls on the timing ofacquiring time information. The determiner 164 determines that there isan overlapped timing not only when the timings are the same but alsowhen the timings are shifted from each other by less than a given timeperiod.

Here, the given time period is a time period set in consideration of thetime required for the control procedure described later fromestablishment of connection to disconnection. This is set so that thetime for a peripheral (for example, the peripheral 202) to communicatewith the central 100 does not overlap with the time for anotherperipheral (for example, the peripheral 201) to communicate with thecentral 100. Here, the determiner 164 corresponds to determinationmeans.

When the determiner 164 determines that there is an overlapping(duplication), the timing information changer 165 changes the timingpresented by the received timing information. The timing is changed byshifting the timing presented by the received timing information by aspecific interval to a timing later than the timing presented by thetiming information of another peripheral (for example, the peripheral201).

The specific interval is a time period equal to or longer than theabove-mentioned given time period and, for example, two minutes.Moreover, the controller 160 stores the timing information having thetiming changed in the ROM 120 in association with identificationinformation of the transmission source peripheral (for example, theperipheral 202). Here, the timing information changer 165 corresponds totiming information change means.

Based on the timing information changed by the timing informationchanger 165, the change notifier 166 sends to the peripheral 201 orperipheral 202 that is the transmission source of that timinginformation notice of change to change the setting of the timinginformation of that peripheral 201 or peripheral 202 (namely, its owndevice). Here, the change notifier 166 corresponds to changenotification means.

The timekeeper 167 comprises a counter circuit counting the number ofpulses of clock signals of its own device (the central 100). Thetimekeeper 167 measures the time based on the counted number of pulses.Moreover, the controller 160 executes various controls at timings basedon the number of pulses counted by the timekeeper 167. Here, the timemeasured by the timekeeper 167 is periodically corrected through timesynchronization with a global positioning system (GPS) satellite or abase station by a not-shown time information acquirer. Here, thetimekeeper 167 may function in a form of hardware other than thecontroller 160.

The clock signals generator 168 comprises a crystal oscillatorgenerating a reference clock, a variable phase locked loop (PLL)generating clock signals of a desired frequency from the referenceclock, and the like, and generates clock signals of its own device (thecentral 100). The frequency of the clock signals is controlled bychanging the frequency dividing ratio of the variable PLL.

The disconnection request transmitter 169 sends a disconnection requestfor disconnection to the connected peripheral (the peripheral 201 orperipheral 202) via the wireless communicator 110. The disconnectionrequest is sent, for example, when data communication with the connectedperipheral ends or when the user conducts a disconnection operation. Thedisconnection request transmitter 169 corresponds to disconnectionrequest transmission means.

The configuration of the peripherals 201 and 202 according to thisembodiment is described next. Here, the peripheral 201 and peripheral202 have the same configuration and the configuration of the peripheral201 is described as their representative example. In the followingexplanation, the components of the peripheral 202 are referred to by thesame reference numbers of those of the peripheral 201.

As shown in FIG. 3, the peripheral 201 comprises a wireless communicator210, a ROM 220, a RAM 230, an operator 240, a display 250, and acontroller 260.

The wireless communicator 210 comprises, for example, an RF circuit, BBcircuit, LSI, or the like. The wireless communicator 210 conductsBLE-based wireless communication with the central 100 that is anotherwireless communication device via an antenna 211.

The ROM 220 comprises a nonvolatile memory such as a flash memory andstores programs and data for the controller 260 to control variousfunctions.

The RAM 230 comprises a volatile memory and is used as the work area inwhich the controller 260 temporarily stores data for conducting variousoperations.

The operator 240 comprises buttons, switches, and the like, and servesas an interface receiving user operations.

The display 250 comprises, for example, an LCD, EL display, or the like,and displays images according to image data entered from the controller260.

The controller 260 comprises, for example, a CPU. The controller 260executes various programs stored in the ROM 220 (for example, theprogram for realizing the control procedure described later) to controlthe entire operation of the peripheral 201.

The functional configuration of the controller 260 of the peripheral 201is described next. As shown in FIG. 3, the controller 260 functions asan advertisement transmitter 261, a connection request receiver 262, atime corrector 263, a timing information transmitter 264, a timingsetting changer 265, a timekeeper 266, a clock signals generator 267,and a disconnection request receiver 268.

The advertisement transmitter 261 sends advertisement to the central 100via the wireless communicator 210 and antenna 211. The advertisement issent periodically in accordance with program processing or at the timingof a user operation occurring. Here, the advertisement transmitter 261corresponds to notification information transmission means.

The connection request receiver 262 receives a connection request fromthe central 100 via the antenna 211 and wireless communicator 210 andestablishes connection to the central 100. This establishment ofconnection enables data communication with the central 100. Theconnection request receiver 262 corresponds to connection requestreception means.

The time corrector 263 acquires time information sent from the central100 and corrects the time measured by the timekeeper 266 based on thetime information. In other words, the time corrector 263 corrects thetime measured in its own device (the peripheral 201) so as to match thetime measured in the central 100. The time corrector 263 corresponds totime correction means.

The timing information transmitter 264 sends timing information to thecentral 100 via the wireless communicator 210 and antenna 211. Thetiming information is information presenting a timing of its own device(the peripheral 201) connecting to the central 100 and acquiring timeinformation from the central 100. Moreover, it is assumed that thetiming presented by the timing information is stored in the ROM 220 as atime per day, “5:00:00” (5:00 AM), in the initial state. The timinginformation transmitter 264 corresponds to timing informationtransmission means.

The timing setting changer 265 changes the setting of the timinginformation of its own device (the peripheral 201) to timing informationpresenting a changed timing based on notice of change of timinginformation received from the central 100. The timing setting changer265 corresponds to timing setting change means.

The timekeeper 266 comprises a counter circuit counting the number ofpulses of clock signals of its own device (the peripheral 201). Thetimekeeper 266 measures the time based on the counted number of pulses.The time measured by the timekeeper 266 is corrected as appropriate bythe time corrector 263 as described above. Moreover, the controller 260executes various controls at timings based on the number of pulsescounted by the timekeeper 266.

The clock signals generator 267 comprises a crystal oscillatorgenerating a reference clock, a variable PLL generating clock signals ofa desired frequency from the reference clock, and the like, andgenerates clock signals of its own device (the peripheral 201). Thefrequency of the clock signals is controlled by changing the frequencydividing ratio of the variable PLL.

The disconnection request receiver 268 receives a disconnection requestfor disconnection from the central 100 via the antenna 211 and wirelesscommunicator 210, and disconnects from the central 100. Thedisconnection request receiver 268 corresponds to disconnection requestreception means.

The control procedures for the central 100 and peripherals 201 and 202to correct the time and change the timing information are described nextwith reference to FIG. 4.

In the following explanation, a case in which the central 100 andperipheral 201 first execute the entire control procedures and then thecentral 100 and peripheral 202 execute the entire control procedureswill be described. Moreover, it is assumed that no timing information ofthe peripherals is stored in the ROM 120 of the central 100 at the startof the control procedures. In other words, it is assumed that the firstperipheral from which the central 100 acquires timing information is theperipheral 201 and the second peripheral is the peripheral 202.

First, as powered on, the peripheral 201 starts the control procedureand enables the controller 260 to detect occurrence of various events.Various events occur when the user conducts given operations or at thetimings of executing controls based on program processing. Here, thegiven user operations are, for example, an operation to pair the central100 and peripheral 201 (initial authentication), an operation to launcha program of the peripheral 201, and the like.

Here, when any of various events occurs, the controller 260 of theperipheral 201 detects the event that has occurred (Step S201).Detecting the event, the controller 260 of the peripheral 201 identifieswhat is the event. First, the controller 260 of the peripheral 201determines whether the trigger of the control procedure (namely, theevent) is a given user operation (Step S202).

First, the case of being determined to be a given user operation (StepS202; Yes) is entirely described. In such a case, the advertisementtransmitter 261 of the peripheral 201 sends advertisement to the central100, and the connection request receiver 262 of the peripheral 201receives a connection request from the central 100 and establishesconnection to the central 100 (Step S203). On the other hand, theadvertisement receiver 161 of the central 100 scans the channel of afrequency band in which the advertisement is sent to receive theadvertisement sent from the peripheral 201, and the connection requesttransmitter 162 of the central 100 sends a connection request to theperipheral 201 and establishes connection to the peripheral 201 (StepS101).

As the connection is established, the controller 160 of the central 100notifies the peripheral 201 of a data request and the timing informationreceiver 163 of the central 100 receives timing information from theperipheral 201 (Step S102). On the other hand, the timing informationtransmitter 264 of the peripheral 201 sends timing information to thecentral 100 in response to the data request notified by the central 100(Step S204). Here, it is assumed that the timing presented by the timinginformation is “5:00:00” stored in the ROM 220 of the peripheral 201 inthe initial state.

Then, the determiner 164 of the central 100 determines whether thetiming presented by the timing information received from the peripheral201 overlaps with the timing presented by the timing information alreadyreceived from another peripheral (Step S103).

However, as described above, no timing information is stored in the ROM120 of the central 100 so far. Therefore, the determiner 164 of thecentral 100 determines that there is no overlapped timing (Step S103;No). Consequently, the timing information received from the firstperipheral 201 is stored in the ROM 120 of the central 100 as it is.

Subsequently, the controller 160 (or the change notifier 166) of thecentral 100 sends time information and timing information to theperipheral 201 (Step S105). On the other hand, the controller 260 of theperipheral 201 receives the time information and timing information sentfrom the central 100 (Step S205).

The time corrector 263 and timing setting changer 265 of the peripheral201 corrects the time measured by the timekeeper 266 and changes thesetting of the timing information based on the received time informationand timing information (Step S206). However, no change was made to thetiming in the timing information as described above; therefore,actually, the same timing information is overwritten.

Subsequently, the disconnection request transmitter 169 of the central100 sends a disconnection request to the peripheral 201 and disconnectsthe peripheral 201 (Step S106). On the other hand, the disconnectionrequest receiver 268 of the peripheral 201 receives the disconnectionrequest from the central 100 and disconnects the central 100 (StepS212).

Then, the control procedures of the central 100 and peripheral 201 onceend. Now, the central 100 is available for the control procedure withanother peripheral other than the peripheral 201 (namely, the peripheral202).

The processing in the case of being determined to be a given useroperation in the Step S202 (Step S202; Yes) is described above. Theprocessing in the case of being determined not to be a given useroperation in the Step S202 (Step S202; No) is described next.

When it is not a given user operation, the peripheral 201 firstdetermines whether the current time falls on the timing presented by thetiming information (connection timing) (Step S207). If it is not theconnection timing (Step S207; No). The peripheral 201 waits for theconnection timing coming.

If the current time falls on the connection timing (Step S207; Yes), theadvertisement transmitter 261 of the peripheral 201 sends advertisementto the central 100, receives a connection request from the central 100,and establishes connection to the central 100 (Step S208). On the otherhand, the advertisement receiver 161 of the central 100 scans thechannel of a frequency band in which the advertisement is sent toreceive the advertisement sent from the peripheral 201, and theconnection request transmitter 162 of the central 100 sends a connectionrequest to the peripheral 201 and establishes connection to theperipheral 201 (Step S101).

As the connection is established, the timing information receiver 163 ofthe central 100 notifies the peripheral 201 of a data request andreceives null data from the peripheral 201 (Step S102). On the otherhand, the timing information transmitter 264 of the peripheral 201 sendsthe null data in response to the data request notified by the central100 (Step S209).

Then, the determiner 164 of the central 100 determines whether thetiming presented by the timing information received from the peripheral201 overlaps with the timing presented by the timing information alreadyreceived from another peripheral (Step S103).

However, as described above, the central 100 has received the null data,not timing information, from the peripheral 201. Therefore, thedeterminer 164 of the central 100 determines that there is no overlappedtiming (Step S103; No).

Subsequently, the controller 160 of the central 100 sends timeinformation to the peripheral 201 (Step S105). On the other hand, theperipheral 201 receives the time information sent from the central 100(Step S210).

The time corrector 263 of the peripheral 201 corrects the time measuredby the timekeeper 266 based on the received time information (StepS211).

Subsequently, the disconnection request transmitter 169 of the central100 sends a disconnection request to the peripheral 201 and disconnectsthe peripheral 201 (Step S106). On the other hand, the disconnectionrequest receiver 268 of the peripheral 201 receives the disconnectionrequest from the central 100 and disconnects the central 100 (StepS212).

Then, the control procedures of the central 100 and peripheral 201 onceend. Now, the central 100 is available for the control procedure withanother peripheral other than the peripheral 201 (namely, the peripheral202). The processing in the case of being determined not to be a givenuser operation in the above Step S202 (Step S202; No) is describedabove.

The control procedures the central 100 and peripheral 202 start afterthe control procedures of the central 100 and peripheral 201 end aredescribed next. For easier understanding, matters duplicated with theabove-described control procedures of the central 100 and peripheral 201are omitted in the following explanation.

First, as in the above case of the peripheral 201, the controller 260 ofthe peripheral 202 starts the control procedure and detects variousevents (Step S201). As an event is detected, the controller 260 of theperipheral 202 identifies what is the event.

First, the controller 260 of the peripheral 202 determines whether thetrigger of the control procedure (namely, the event) is a given useroperation (Step S202).

The following explanation will be made in regard only to the case ofbeing determined to be a given user operation (Step S202; Yes). Theprocessing in the case of being determined not to be a given useroperation (Step S202; No) is the same processing as in the above case ofthe peripheral 201 and therefore its explanation is omitted.

First, the peripheral 202 and central 100 send/receive advertisement anda connection request and establish connection as in the above case ofthe peripheral 201 (Steps S203 and S101).

As the connection is established, the controller 160 of the central 100notifies the peripheral 202 of a data request and the timing informationreceiver 163 of the central 100 receives timing information from theperipheral 202 (Step S102). On the other hand, the timing informationtransmitter 264 of the peripheral 202 sends timing information to thecentral 100 in response to the data request notified by the central 100(Step S204). Here, it is assumed that the timing presented by the timinginformation is “5:00:00” stored in the ROM 220 of the peripheral 202 inthe initial state.

Then, the determiner 164 of the central 100 determines whether thetiming presented by the timing information received from the peripheral202 overlaps with the timing presented by the timing information alreadyreceived from another peripheral (Step S103).

Here, the timing information already received from the peripheral 201 isstored in the ROM 120 of the central 100. Therefore, the determiner 164of the central 100 compares the timing information of the peripheral 201stored in the ROM 120 with the timing information received from theperipheral 202 this time.

As a result, the timing presented by the timing information receivedfrom the peripheral 202 this time is the same “5:00:00” as the timingpresented by the timing information of the peripheral 201. Therefore,the determiner 164 of the central 100 determines that there is anoverlapped timing (Step S103; Yes).

In such a case, the timing information changer 165 of the central 100shifts the timing presented by the timing information received from theperipheral 202 by the above-mentioned given time period (2 minutes inthis case) to change the timing from “5:00:00” to “5:02:00” (Step S104).The central 100 stores the changed timing information in the ROM 120.

Subsequently, the controller 160 (or the change notifier 166) of thecentral 100 sends time information and the changed timing information(notice of change) to the peripheral 202 (Step S105). On the other hand,the controller 260 of the peripheral 202 receives the time informationand timing information (notice of change) sent from the central 100(Step S205).

The time corrector 263 and timing setting changer 265 of the peripheral202 corrects the time measured by the timekeeper 266 and changes thesetting of the timing information based on the received time informationand changed timing information (Step S206).

Subsequently, the disconnection request transmitter 169 of the central100 sends a disconnection request to the peripheral 202, and thedisconnection request receiver 268 of the peripheral 202 receives thedisconnection request from the central 100 and disconnects the central100 (Steps S106 and S212).

Then, the control procedures of the central 100 and peripheral 202 onceend. Now, the central 100 is available for the control procedure withanother peripheral other than the peripherals 201 and 202 (none in thisembodiment).

As described above, the peripherals 201 and 202 send to the central 100timing information presenting a timing of acquiring time information.The central 100 changes the timing in the received timing information sothat the timing presented by the timing information received from aperipheral (for example, the peripheral 202) does not overlap with thetiming presented by the already received timing information of anotherperipheral (for example, the peripheral 201). Moreover, the central 100makes the peripheral in question (for example, the peripheral 202)change the setting of the timing information based on the changed timinginformation.

As described above, the wireless communication system 1 of thisembodiment can prevent the timings of the peripherals 201 and 202acquiring time information from overlapping. Consequently, it ispossible to eliminate the risk of occurrence of unsuccessful connectionand failed time synchronization as a result of the peripherals 201 and202 attempting to connect to the central 100 and acquire timeinformation at the same time.

Therefore, the wireless communication system 1 of this embodiment canrealize time synchronization even if there are two peripherals (theperipherals 201 and 202) for the central 100 to time-synchronize.

An embodiment is described above. The above embodiment is given by wayof example. Therefore, the specific configuration and processing detailsof the peripherals 201 and 202 and central 100 are not limited to thosedescribed in the embodiment. A modified embodiment of the aboveembodiment is described below.

Modified Embodiment

When the central 100 receives timing information from the peripherals201 and 202 and the timings presented by the timing information receivedfrom the peripherals 201 and 202 overlap, the central 100 changes atiming by shifting the timing by a given time period or more that is setin consideration of the time required for the control procedure fromestablishment of connection to disconnection. The given time period isnot limited to the above and may be set in consideration of clock rateinformation of the peripherals 201 and 202.

For example, as a modified embodiment of the central 100, a central 300is configured as shown in FIG. 5. A controller 170 of the central 300has the same configuration as the controller 160 of the central 100 andadditionally comprises a clock rate information receiver 171. The clockrate information receiver 171 corresponds to clock rate informationreception means. In FIG. 5, the same components as of the central 100are referred to by the same reference numbers.

On the other hand, as a modified embodiment of the peripherals 201 and202, a peripheral 401 is configured as shown in FIG. 6. A controller 270of the peripheral 401 has the same configuration as the controller 260of the peripherals 201 and 202 and additionally comprises a clock rateinformation transmitter 269. The clock rate information transmitter 269corresponds to clock rate information transmission means. In FIG. 6, thesame components as of the peripherals 201 and 202 are referred to by thesame reference numbers.

Between the central 300 and peripheral 401 configured as describedabove, the peripheral 401 sends clock rate information to the central300 and the central 300 sets a given time period based on the receivedclock rate information. The specific interval to shift the timing forchanging the timing is set to this given time period or longer. Here,the clock rate information is information presenting the deviation ofthe time measured by the peripheral 401 (namely, daily rate, monthlyrate, and the like).

Even when there are multiple peripherals 401 for the above-describedcentral 300 to time-synchronize and the times measured by the multipleperipherals vary due to time deviation as a result of the daily rate,monthly rate, and the like, the intervals between the timings in thetiming information of the multiple peripherals 401 are specificintervals larger than the variation. Therefore, the multiple peripherals401 simultaneously attempting to connect to the central 300 due todeviation of the times the peripherals 400 individually measure iscertainly prevented.

In the above-described embodiment, the central 100 time-synchronizes twoperipherals 201 and 202. However, there may be three or moreperipherals.

When there are three or more peripherals and there are two or morepieces of timing information already received in the determination ofoverlapped timing by the central 100 (Step S103), the timing is changed(Step S104) by shifting the timing by a specific interval (for example,2 minutes) from the latest timing among those pieces of timinginformation. In other words, the settings of the timings presented bythe timing information of the peripherals can be changed so that“5:00:00” is set for the first peripheral; “5:02:00,” for the secondperipheral; “5:04:00,” for the third peripheral; and so on.

In the above-described embodiment, the timing presented by the timinginformation is changed to a later timing by a specific interval (forexample, 2 minutes) when necessary. However, the timing may be changedto an earlier timing by a specific interval (for example, 2 minutes).Moreover, when there are three or more peripherals, the settings of thetimings presented by the timing information of the peripherals may bechanged so that “5:00:00” is set for the first peripheral; “4:58:00,”for the second peripheral; “4:56:00,” for the third peripheral; and soon. Here, the specific interval by which the timing is shifted to changeis not limited to two minutes.

As described above, when the timing is shifted by a specific intervaland changed either to an earlier timing or to a later timing than thetiming presented by the timing information of another peripheral, thereis no need of determining whether to change to an earlier timing or to alater timing at each time the timing is changed. Moreover, for aperipheral from which new timing information is received, the timing cansimply be changed by shifting the timing by a specific interval alwaysin one direction and there is no need of determining whether that timingis available. This is because shifting by an interval as small as twominutes as in the above-described embodiment allows for setting oftimings of several hundred peripherals per 24 hours. Moreover, it ispossible to change the settings of the timings in sequence without thenecessity of deleting the timing information of a peripheral of whichparing with the central 100 is canceled or taking into account a timingthat accordingly becomes available. Therefore, the processing of thecentral 100 to change the timings can be simplified.

In the above-described embodiment, the central 100 and peripherals 201and 202 wirelessly communicating with each other based on the BLE areused as exemplary communication devices. However, the present disclosureis not confined to a wireless communication device conducting wirelesscommunication based on the BLE. For example, the present disclosure maybe a wireless communication device conducting wireless communicationbased on the WiFi (registered trademark) or ZigBee (registeredtrademark).

Moreover, in the above-described embodiment, the determiner 164determines that there is no overlapped timing when null data arereceived from the peripheral 201. This is not restrictive. For example,the determiner 164 may determine that there is no overlapped timing whenno timing information or null data are received within a specific timeperiod.

Moreover, in the above-described embodiment, when the peripheral 201changes the setting of the timing information based on the receivedtiming information, substantially the same timing information isoverwritten if no change is made to the timing. This is not restrictive.For example, it may be possible to continue to retain the retainedtiming information without overwriting substantially the same timinginformation.

Moreover, in the above-described embodiment, the controller 160,controller 260, controller 170, and controller 270 conduct the controlprocedures to correct the time and change the timing information. Thisis not restrictive. For example, the wireless communicator 110 andwireless communicator 210 may conduct a part or all of the controlprocedure. In other words, the advertisement receiver 161, connectionrequest transmitter 162, timing information receiver 163, determiner164, timing information changer 165, change notifier 166, timekeeper167, clock signals generator 168, disconnection request transmitter 169,clock rate information receiver 171, advertisement transmitter 261,connection request receiver 262, time corrector 263, timing informationtransmitter 264, timing setting changer 265, timekeeper 266, clocksignals generator 267, disconnection request receiver 268, and clockrate information transmitter 269 may constitute a single controller oreach individually comprise a controller to execute each operation, orthe wireless communicator 110 and wireless communicator 210 may executethe operations.

Moreover, the central 100 and peripherals 201 and 202 according to thepresent disclosure may not be realized by the above device and, forexample, a computer may realize the function of the central 100 and thefunction of the peripherals 201 and 202 by executing programs. Theprograms for realizing the function of the central 100 and the functionof the peripherals 201 and 202 may be stored on a non-transitorycomputer-readable recording medium such as a universal serial bus (USB)memory, compact disc-read only memory (CD-ROM), digital versatile disc(DVD), and hard disk drive (HDD), or downloaded to a computer via anetwork.

The foregoing describes some example embodiments for explanatorypurposes. Although the foregoing discussion has presented specificembodiments, persons skilled in the art will recognize that changes maybe made in form and detail without departing from the broader spirit andscope of the invention. Accordingly, the specification and drawings areto be regarded in an illustrative rather than a restrictive sense. Thisdetailed description, therefore, is not to be taken in a limiting sense,and the scope of the invention is defined only by the included claims,along with the full range of equivalents to which such claims areentitled.

What is claimed is:
 1. A wireless communication device comprising aprocessor, wherein the processor measures time; acquires timeinformation from another wireless communication device and corrects themeasured time; sends timing information presenting a timing of acquiringthe time information to the other wireless communication device; andreceives notice of change of the timing information from the otherwireless communication device and changes a setting of the timinginformation based on the notice of change.
 2. An electronic timepiececomprising the wireless communication device according to claim
 1. 3. Awireless communication method, comprising: a timing informationreception step of receiving from a wireless communication device timinginformation presenting a timing of the wireless communication deviceacquiring time information; a determination step of determining whetherthe timing presented by the timing information received in the timinginformation reception step overlaps with a timing presented by timinginformation of another wireless communication device other than thewireless communication device; a timing information change step ofchanging the timing presented by the timing information when theoverlapping is determined in the determination step; and a changenotification step of sending to the wireless communication device noticeof change to change a setting of the timing information of the wirelesscommunication device based on the changed timing information.
 4. Thewireless communication method according to claim 3, further comprising:a clock rate information reception step of receiving from the wirelesscommunication device clock rate information presenting deviation of thetime measured by the wireless communication device, wherein in thetiming information change step, the timing is changed based on the clockrate information.
 5. The wireless communication method according toclaim 3, wherein in the timing information change step, the timing ischanged by shifting the timing by a specific interval either to anearlier timing or to a later timing than the timing presented by thetiming information of the other wireless communication device.
 6. Thewireless communication method according to claim 4, wherein in thetiming information change step, the timing is changed by shifting thetiming by a specific interval either to an earlier timing or to a latertiming than the timing presented by the timing information of the otherwireless communication device.
 7. A non-transitory computer-readablerecording medium on which programs are recorded, wherein the programsallow a computer to function as: timing information receiver whichreceives from a wireless communication device timing informationpresenting a timing of the wireless communication device acquiring timeinformation; determiner which determines whether the timing presented bythe timing information received by the timing information receiveroverlaps with a timing presented by timing information of anotherwireless communication device other than the wireless communicationdevice; timing information changer which changes the timing presented bythe timing information when the overlapping is determined by thedeterminer; and change notifier which sends to the wirelesscommunication device notice of change to change a setting of the timinginformation of the wireless communication device based on the changedtiming information.